Development of InAlN HEMTs for space application

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dc.contributor.advisor Parbrook, Peter James en
dc.contributor.advisor Barnes, Andrew en
dc.contributor.author Smith, Matthew D.
dc.date.accessioned 2016-02-05T10:10:53Z
dc.date.available 2016-02-05T10:10:53Z
dc.date.issued 2016
dc.date.submitted 2016
dc.identifier.citation Smith, M. D. 2016. Development of InAlN HEMTs for space application. PhD Thesis, University College Cork. en
dc.identifier.endpage 221 en
dc.identifier.uri http://hdl.handle.net/10468/2257
dc.description.abstract This thesis investigates the emerging InAlN high electron mobility transistor (HEMT) technology with respect to its application in the space industry. The manufacturing processes and device performance of InAlN HEMTs were compared to AlGaN HEMTs, also produced as part of this work. RF gain up to 4 GHz was demonstrated in both InAlN and AlGaN HEMTs with gate lengths of 1 μm, with InAlN HEMTs generally showing higher channel currents (~150 c.f. 60 mA/mm) but also degraded leakage properties (~ 1 x 10-4 c.f. < 1 x 10-8 A/mm) with respect to AlGaN. An analysis of device reliability was undertaken using thermal stability, radiation hardness and off-state breakdown measurements. Both InAlN and AlGaN HEMTs showed excellent stability under space-like conditions, with electrical operation maintained after exposure to 9.2 Mrad of gamma radiation at a dose rate of 6.6 krad/hour over two months and after storage at 250°C for four weeks. Furthermore a link was established between the optimisation of device performance (RF gain, power handling capabilities and leakage properties) and reliability (radiation hardness, thermal stability and breakdown properties), particularly with respect to surface passivation. Following analysis of performance and reliability data, the InAlN HEMT device fabrication process was optimised by adjusting the metal Ohmic contact formation process (specifically metal stack thicknesses and anneal conditions) and surface passivation techniques (plasma power during dielectric layer deposition), based on an existing AlGaN HEMT process. This resulted in both a reduction of the contact resistivity to around 1 x 10-4 Ω.cm2 and the suppression of degrading trap-related effects, bringing the measured gate-lag close to zero. These discoveries fostered a greater understanding of the physical mechanisms involved in device operation and manufacture, which is elaborated upon in the final chapter. en
dc.description.sponsorship EMBARK initiative, ESA grant 4000104741/11/NL/Cbi en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher University College Cork en
dc.rights © 2016, Matthew D. Smith. en
dc.rights.uri http://creativecommons.org/licenses/by-nc-nd/3.0/ en
dc.subject Transistors en
dc.subject Space en
dc.subject Nitrides en
dc.subject Reliability en
dc.subject Semiconductors en
dc.subject Radiation en
dc.subject Electronics en
dc.title Development of InAlN HEMTs for space application en
dc.type Doctoral thesis en
dc.type.qualificationlevel Doctoral en
dc.type.qualificationname PHD (Engineering) en
dc.internal.availability Full text available en
dc.check.info No embargo required en
dc.description.version Accepted Version
dc.contributor.funder Irish Research Council en
dc.contributor.funder European Space Agency en
dc.description.status Not peer reviewed en
dc.internal.school Electrical and Electronic Engineering en
dc.internal.school Tyndall National Institute en
dc.check.type No Embargo Required
dc.check.reason No embargo required en
dc.check.opt-out Not applicable en
dc.thesis.opt-out false
dc.check.embargoformat Not applicable en
ucc.workflow.supervisor peter.parbrook@tyndall.ie
dc.internal.conferring Spring 2016 en


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